SANTIAGO, Aug 30 (Reuters) - World top copper producer Codelco posted a pre-tax profit of $318 million in the first six months of the year, a drop of 74 percent, the company said on Friday, as the state miner struggled with falling prices globally and labor strife at home.

Chile’s state miner said production costs had fallen slightly to $1.42 per pound of copper. (Reporting by Dave Sherwood)